๐ฃ Cannonball metastases = large, round, well-defined pulmonary metastases seen on CXR or CT.
They resemble โcannonballsโ due to their spherical appearance.
๐ซ Most often due to **haematogenous spread** of malignancy. Their discovery usually indicates advanced disease.
๐ฏ Common Primary Cancers Associated
- Renal Cell Carcinoma (RCC): Classic cause; often presents late with lung mets. ๐ข
- Choriocarcinoma: Aggressive; spreads rapidly to lung, causing hemorrhagic cannonballs. ๐ฉโ๐ผ
- Testicular Cancer (NSGCT): Young men may present with cannonball lesions on CXR. โฝ
- Prostate Cancer: Rare, usually very advanced disease. ๐ง
- Breast Cancer: Can produce pulmonary metastases but less often โcannonball-like.โ ๐
- Sarcomas: Especially osteosarcoma & soft tissue sarcoma. ๐ฆด
- Colorectal Cancer: Occasionally produces round pulmonary metastases. ๐ฝ๏ธ
๐ Radiological Appearance
- Chest X-ray: Multiple, round, well-circumscribed opacities in both lungs โ โsnowstormโ of nodules. ๐จ๏ธ
- CT Scan: Precise size, number, distribution; assesses pleura & nodes. ๐ฅ๏ธ
- Pattern: Bilateral, widespread, random distribution โ hallmark of haematogenous spread. ๐
๐ฉบ Clinical Presentation
- Often asymptomatic: Incidental finding during staging scans.
- Cough & Dyspnoea: From bulk disease or airway irritation. ๐ฎโ๐จ
- Hemoptysis: Due to vascular invasion. ๐จ
- B Symptoms: Weight loss, fever, night sweats, fatigue. โก
๐ Differential Diagnosis
- Primary lung cancer (usually spiculated, not rounded).
- Granulomatous infection โ TB, fungal disease, sarcoid ๐ฆ .
- Rheumatoid nodules (in seropositive RA). โ
- Wegenerโs (GPA) โ cavitating nodules. ๐งฉ
- Septic emboli โ esp. IVDU or endocarditis. ๐
๐งช Diagnostic Workup
- Imaging: CXR โ CT chest โ PET-CT for staging.
- Biopsy: CT-guided or bronchoscopic biopsy for histology & IHC. ๐ฌ
- Tumour Markers:
- ฮฒ-hCG โ choriocarcinoma/testicular cancer.
- AFP โ germ cell tumours.
- PSA โ prostate cancer.
- Systemic staging: Abdomen/pelvis imaging for RCC, germ cell, colorectal. ๐ฅ๏ธ
๐ Management
- Depends on primary tumour:
- RCC โ TKIs, immunotherapy (pembrolizumab, nivolumab). ๐
- Choriocarcinoma โ highly chemo-sensitive (methotrexate, EMA-CO). ๐
- Testicular cancer โ BEP chemo regimen (Bleomycin, Etoposide, Cisplatin). โก
- Breast โ systemic chemo, hormonal therapy, targeted (HER2 agents). ๐
- Surgical resection (metastasectomy): Occasionally considered in limited disease โ e.g., osteosarcoma. ๐ช
- Palliative care: Dyspnoea control (oxygen, opioids), pain management. ๐๏ธ
๐ Prognosis
Generally poor โ indicates advanced systemic disease.
โณ Prognosis varies by tumour biology:
๐ Testicular cancer โ curable, even with cannonball mets (5-year survival >80%).
โ ๏ธ RCC, sarcoma, breast, colon โ worse outcomes, dependent on systemic control.
๐ Prognosis linked more to primary cancer type & treatment response than lung disease itself.